We use it to add bridged adapters with VLAN tags to our hypervisors
Bridging works great, but it's kind of fun to see this at the proxy ARP level.
Very well written, and I like how he used strace on all those examples.
If you want to experiment at a low cost, though, there's the Banana PI BPI-R1. A ~$70 linux ARM dev board with 5 GB ethernet interfaces.
An example using bridge to packet capture. https://github.com/williamknows/PiTap